Apparatus for cleaning strip material

ABSTRACT

Strip material cleaning apparatus wherein the material being cleaned is positioned in the nips formed between rotary cleaning tools mounted for rotation on parallel shafts and respective back-up rolls, the latter being associated with drive means for positive forwarding of the material being cleaned, the rolls being rotated in the direction of the forwarding of the material, together with one half of the total amount of said parallel shafts, the other half of said shafts being rotated in the opposite direction. The shaft which is the first one of said parallel shafts in the direction of the forwarding of the material being cleaned is rotated in the course of a cleaning operation solely in the direction opposite to that of the forwarding of the material being cleaned.

United States Patent Salukvadze et al.

11] 3,803,661 [451 Apr. 16,1974

[ APPARATUS FOR CLEANING STRIP MATERIAL [76] Inventors: ,ViktorSamsonovich Salukvadze,

' Parkovaya ulitsa, 42, kv. 53;

Vyacheslav Egorovich Musyakin, Sirenevy bulvar, 36, kv. 51, both ofMoscow, USSR.

[22] Filed: July 7, 1972 [21] App]. No.: 269,807

[52] US. Cl. 15/77 [51] Int. Cl A46b 13/02 [58] Field of Search 15/77,102; 51/DIG. 8, 51/22, 23, 78, 87 R [56] References Cited UNITED STATESPATENTS 2,278,944 4/1942 Quigley et al 15/77 2,321,179 6/1943 Boyer15/77 3,245,102 4/1966 Gallmeyer et al. 15/77 Primary Examiner--EdwardL. Roberts Attorney, Agent, or Firm-Holman & Stern 57 ABSTRACT Stripmaterial cleaning apparatus wherein the material being cleaned ispositioned in the nips formed between rotary cleaning tools mounted forrotation on parallel shafts and respective back-up rolls, the latterbeing associated with drive means for positive forwarding of thematerial being cleaned, the rolls being rotated in the direction of theforwarding of the material, together with one half of the total amountof said parallel shafts, the other half of said shaftsbeing r0- tated inthe opposite direction. The shaft which is the first one of saidparallel shafts in the direction of the forwarding of the material beingcleaned is rotated in the course of a cleaning operation solely in thedirection opposite to that of the forwarding of the material beingcleaned.

3 Claims, 5 Drawing Figures PATENT EDAPR 16 I974 4 SHEET 1 BF 2APPARATUS FOR CLEANING STRIP MATERIAL The invention relates to thetechniques of cleaning the surface of a material, and, moreparticularly, it relates to apparatus for cleaning strip material.

The invention can be employed to utmost advantage for cleaning sheetmaterial practically of any thickness, particularly of thin sheetshaving the thickness within a range from 0.2 mm to 4.0 mm.

There are known apparatus for cleaning sheet material positivelyforwarded through the nips formed by rotary cleaning tools mounted onparallel shafts and by the respective back-up rolls cooperating with thetools. (See, for example, US. Pat. No. 2,907,151, 1959).

In these known apparatus the strip material being cleaned is positivelyforwarded by at least two spaced pairs of pulling rollers, the rotarycleaning tools and their respective back-up rolls being arranged in thespace between these two pairs. The back-up rolls are freely rotatableabout their shafts and are rotated, as the strip material is beingpositively forwarded, by the friction forces between the material beingcleaned and the peripheries of these rolls.

These known apparatus provide for cleaning of a material having athickness sufficient for maintaining longitudinal stability of thismaterial against the action of the friction forces developed in thecourse of a cleaning operation.

A disadvantage of these known apparatus is the fact that they arevirtually incapable of effecting continuous cleaning of thin sheets (thethickness being from 0.2 to 0.5 mm) along the entire length of thesheets.

A reason for this fact is that as the trailing edge of the materialleaves the nip of the first, or upstream (in the direction of theforwarding of the material) pair of the pulling rollers, the material,when it is in the form of thin sheets having relatively low rigidity, nolonger maintains its longitudinal stability against the friction forcesdeveloped in the course of a cleaning operation under the action of therotating cleaning tools either in the area intermediate of the axis ofthe shaft carrying pulling rollers, in case the direction of therotation of the last-mentioned shaft is that of the direction of theforwarding of the sheets, or else in the area intermediate of the axisof the first pair of pulling rollers and the axis of the shaft carryingthese rotating cleaning tools, in case the direction of the rotation ofthis shaft is opposite to the direction of the forwarding of the sheets.In both cases only a part of the length of a sheet can be cleaned.

Furthermore, in these known apparatus the spacing between the two pairsof pulling rollers limits the permissible range of the lengths of sheetsto be cleaned, because the length of a sheet is substantially greaterthan this spacing.

It is the principal object of the present invention to provide anapparatus for cleaning strip material, wherein this material ispositively forwarded and the shafts carrying the rotary cleaning toolsis rotated in such directions, that the apparatus is capable ofhighquality cleaning not only of sufficiently thick strip material, butalso of continuous cleaning of thin sheets of practically any thickness.

This and other objects are attained in an apparatus for cleaning stripmaterial positively forwarded through the nips formed between rotarycleaning tools mounted on parallel shafts and the respective back-uprolls, each said back-up roll being mounted in opposition to therespective one of said shafts, in which apparatus, in accordance withthe invention, all said back-up rolls are associated with drive meansand are adapted for rotation in the direction of the forwarding of thestrip material being cleaned, together with one half of the total amountof said parallel shafts carrying thereon said rotary cleaning tools, theother half of the total amount of said parallel shafts being rotated inthe opposite direction; one of said parallel shafts, which is the firstone in the direction of the forwarding of said strip material beingcleaned, being adapted for rotation in the course of a cleaningoperation solely in a direction opposite to the direction of theforwarding of said material being cleaned.

With the apparatus having been designed in the lastdescribed manner, thestrip material cleaned thereby maintains, as it is being forwarded,adequate longitudinal stability over the area intermediate of the shaftscarrying thereon the rotary cleaning tools, which provides forhigh-quality cleaning not only of strip material, but also of individualthin sheets of practically any thickness.

To provide for cleaning of individual, different lengths of material, itis advisable that at least one of said parallel shafts carrying saidcleaning tools and the respectively arranged one of said back-up rollsshould be mounted for adjustment in the direction of the forwarding ofsaid material being cleaned.

It is further advisable, in order to ensure high-quality cleaning ofstrip material and sheets, particularly, those having a thickness inexcess of 2.0 mm, that each said shaft should carry thereon said rotarycleaning tools adapted for rotation in opposite directions and soarranged relative to one another that the linear speed of said materialbeing cleaned in the areas of the contact thereof with said back-up rollis the same, the total width of said tools rotated in one of saidopposite directions being at least equal to the total width of saidtools rotated in the other one of said opposite directions, all saidtools on all said parallel shafts being so arranged that the respectivewidths thereof successively and altematingly span the total width ofsaid material being cleaned.

In case the total width of said tools rotated in said one of saidopposite directions is greater than the total width of said toolsrotated in said other one of said opposite directions, the differencebetween said total widths should not be in excess of a value determinedfrom the expression: ,7

where f is the factor of the slipping friction between said materialbeing cleaned and said back-up roll;

F is the factor of friction drag or pull exerted by said cleaning toolupon said material being cleaned;

B is the width of the material being cleaned.

It is highly essential, in order to solve an important problem ofcombining a high quality of the cleaning with a high productivity ofapparatus, that said rotary cleaning tools should be in the form ofrotary cutting tools including each a plurality of radially extendinglengths of wire, said lengths having the ends thereof, disposedinternally of said tools, connected to one another, said lengths furtherhaving the lateral sides thereof adjacent to said connected ends pressedto one another, the opposite free ends of said lengths of wire forming acommon cutting surface of said tool in the shape of a body of rotation,the ratio of the total area of the faces of said free ends of saidlengths to the total area of said cutting surface being within a rangefrom 0.2 to 0.9.

The present invention will be further described in connnection withseveral embodiments thereof, with reference being had to the appendeddrawings, wherein:

FIG. 1 shows schematically a plan view of an apparams for cleaning stripmaterial, having two parallel shafts carrying rotary cleaning tools, inaccordance with the invention;

FIG. 2 is a sectional view taken along line IIII of FIG. 1;

FIG. 3 is a front view of an apparatus for cleaning strip materialwherein, in accordance with the invention; a shaft and the respectiveback-up roll are adjustable in the direction of the forwarding of thematerial being cleaned (the material being shown in crosssection);

FIG. 4 is a partly broken away front view of an apparatus for cleaningstrip material wherein, in accordance with the invention, each shaftcarries cleaning tools connected for rotation in opposite directions;and

FIG. 5 is a front view of the apparatus illustrated in FIG. 4, with thematerial being cleaned shown in crosssection. I

Referring now in particular to the appended drawings, the hereindisclosed apparatus for cleaning strip material includes a plurality ofparallel shafts (two shafts in the presently described embodiment) 1 and2 (FIG. 1) carrying thereon rotary cleaning tools 3 and 4, the stripmaterial being positively forwarded intermediate these cleaning toolsand their respective backup rolls 5 mounted in opposition to therespective shafts.

In accordance with the present invention, all the back-up rolls 5 (FIG.2) are driven ones, the rolls being positively rotated in. the directionindicated by the arrow A, one half of the parallel shafts carryingthereon the cleaning tools being rotated in the same direction A, andthe other half of these parallel shafts being rotated in the oppositedirection indicated by the arrow line C (FIG. 1). g

(Symbols B and b will be used hereinafter to indicate, respectively, thelateral width of the material being cleaned and the width of thecleaning tools).

The shaft 1 which is the first or up-st-ream one in the direction of theforwarding of the material 6 is rotated throughout the cleaningoperation solely in the direction indicated by the arrow line C, inopposition to the direction of the travel of the material being cleaned.

The shafts l and 2 are journalled in bearings 7 mounted on supports 8included in the apparatus. The back-up rolls 5. (FIG. 2) are journalledin bearings 9 mounted on a cross bar 10 movable in guideways 11 underthe action of the back-up roll vertical adjustment actuator 12. Thisvertical adjustment of each one of the back-up rolls 5 is necessary forestablishing a desired value of contact pressure between the stripmaterial 6 being cleaned and the respective rotary cleaning tool.

In the presently described embodiment each cleaning tool-carrying shaftis independently rotated by an electric motor 13 associated therewith.Each back-up roll 5 is likewise independently rotated by an associatedelectric motor 14. The independent driving motors offer independentcontrol of the speed of the rotation of the cleaning tool and of itsrespective back-up roll.

The herein disclosed apparatus operates as follows. The motors 13driving the respective shafts 1 and 2 are energized, and the motors l4driving the respective back-up rolls are energized, too,

Rotation from the motor 13 is transmitted to the input shaft of areducing gear 15, and from the output shaft of this reducing gearrotation is further transmitted by any suitable known means to therespective shafts l and 2 carrying the cleaning tools 3 and 4. The shaft1 is rotated in the direction C, i.e., in opposition to the travel ofthe strip material 6, whereas the shaft 2 is rotated in the direction A,i.e., in the direction of the travel of the strip material 6.

Rotation from each motor 14 is transmitted to the input shaft of areducing gear 16, and from the output shaft of this reducing gearrotation is transmitted by any suitable known means to the respectiveone of the back-up rolls 5 which are thus rotated in the direction A ofthe travel of the strip material 6.

The strip material 6 is forwarded in the direction A by the first, orupstream one of the back-up rolls 5. As the leading edge of the stripmaterial 6 engages the second, or downstream one of the back-up rolls 5,the back-up roll vertical adjustment actuators 12 are operated, wherebythe strip material 6 is pressed by the back-up rolls 5 against therespective rotating cleaning tools 3 and 4.

The design of the herein disclosed apparatus ensures that the stripmaterial 6 being cleaned, as it is being positively forwarded by theback-up rolls 5, retains its longitudinal stability throughout the areabetween the two parallel shafts l and 2, whereby the apparatus iscapable of continuous, high-quality cleaning not only of strip materialand thick sheets, but also of thin sheets of any thickness ranging from0.2 mm to 4.0 mm.

Alternatively, the herein disclosed apparatus may be operated, asfollows.

The strip material 6 is forwarded in'the direction indicated by thearrow line A by the upstream back-up roll 5. As the leading edge of thestrip material 6 engages the second, or downstream back-up roll 5, the10 tuators 12 are operated to adjust vertically the two back-up 5,whereby the latter press the strip material 6 toward the respectivecleaning tools 3 and 4. In this way there is cleaned a length of thestrip material 6, equal to double distance between the axes of theshafts l and 2. Then the peripheral linear speed of the rotatingcleaning tool 4 is gradually reduced to the linear speed of theforwarding of the material 6, whereby the cleaning tool starts acting asa pulling transport roller, i.e., in this case the rotating cleaningtool together with its respective back-up rool effect positiveforwarding of the material being cleaned. Cleaning of the remaininglength of the strip material 6, i.e., of the length upstream of thefirst roll 5, is effected by the cleaning tool 3.

In this way, too, there is ensured continuous cleaning not only of stripmaterial and relatively thick sheets, but of thin sheets, e.g., withthickness ranging from 0.2 mm to 4.0 mm, as well.

To clean successive individual lengths of a material, it is advisable,in accordance with the invention, that at least one of the two parallelshafts (the shaft 2 in the presently described embodiment) carrying therotary cleaning tools and its respective back-up roll 5 should bemounted for adjustment longitudinally of the direction of the forwardingof the material 6 being cleaned.

Such longitudinal adjustment is made possible by the supports 8 carryingthe bearings 7 of the shaft 2 and the crossbar 10 carrying the bearings9 of the respective back-up roll 5 being mounted on a longitudinallymovable plate 17. The same plate 17 in this case has mounted thereon thedrive effecting rotation of the shaft 2 carrying the cleaning tool 4, aswell as the drive of the respective back-up roll 5.

The plate 17 can be reciprocated along tracks 18 longitudinally of thedirection of the arrow A with the help of an electric motor 19.

With the herein disclosed apparatus constructed in the last-describedmanner, its operation ability be comes broadened, i.e., longitudinaladjustment of the plate 17 in the direction of the arrow line A, i.e.,in the direction of the forwarding of the material 6 being cleaned,provides for continuous cleaning of sheets of various lengths.

Let us now consider another embodiment of the present invention, whereinthe parallel shafts 1 and 2 (FIG. 4), in accordance with the invention,carry rotary cleaning tools 20, 21 and 22, 23 rotated in the oppositedirections and so arranged relative to one another that the linear speedof the material 6 being cleaned in the areas of the engagement thereofwith the back-up rolls 5 should be the same. The cleaning tools 20 arenonrotatably mounted on the shaft 1 for rotation together therewith,while the cleaning tools 21 are mounted for free rotation about theshaft 2 with the help of their bearings 24 and are positively rotated ina direction opposite to that of the forwarding of the material 6.

The cleaning tools 22 are mounted for free rotation about the shaft 1with the help of their respective bearings 24 and are rotated in thedirection of the arrow A, i.e., in the direction of the forwarding ofthe material 6 being cleaned, while the cleaning tools 23 arenonrotatably mounted on the shaft 2 for rotation together therewith,i.e., in the direction of the arrow A.

In this case the total lateral width Eb, of the cleaning tools 20 and 21rotating in one direction indicated by the arrow C should be not belowthe total lateral width Zb of the cleaning tools 22, 23 rotating in theopposite direction indicated by the arrow A.

The cleaning tools 20 and 21, 22 and 23 are mounted in a staggeredrelationship on the respective ones of the shafts l and 2, so that thelateral width thereof successively and alternatingly spans the entirelateral width B of the material 6 being cleaned.

In the presently described embodiment of the invention the rotation ofthe cleaning tools 22 and 21 that are freely rotatable, respectively,about the shafts l and 2 is effected by an electric motor 13 (FIG. 5)from which rotation is transmitted to the input shaft of a reducing gear15, from the output shaft of which rotation is transmitted through agearing including two bevel gear couples 25 and 26. In each bevel gearcouple 25 the driving gear is non-rotatably mounted on the respeetiveone of the shafts 1 and 2, and the driven gear is rigidly coupled to thedriving gear of the bevel gear couple 26. The driven gear of the bevelgear couple 26 is non-rotatably mounted on an intermediate shaft 27journalled for rotation in bearings 28 mounted on the supports 8 (FIG.4) of the apparatus.

The intermediate shaft 27 (FIG. 5) if drivingly connected with thecleaning tools 21 and 22, mounted for free rotation about the respectiveshafts 2 and 1, by chain transmission means 29.

The last described embodiment of the present invention is operated asfollows. I

The electric motors 13 (FIG.'4) are energized to drive the shafts l and2, and the electric motors 14 are energized to drive the back-up rolls5. The shaft 1 is thus rotated in the direction indicated by the arrowline C, i.e., in opposition to the forwarding of the strip material 6,whereas the shaft 2 is rotated in the direction indicated by the arrowline A, i.e., in the direction of the forwarding of the strip material6.

As' the leading edge of the strip material 6 engages the roll 5 which isthe first, or upstream one in the direction of the progress of thematerial 6, the actuator 12 (FIG. 5) is operated to effect verticaladjustment of this back-up roll 5, whereby the material 6 is pressed bythe last-mentioned roll to the respective cleaning tools 20 and 22. Inthis way a part of the total width B of the material 6 is cleaned.Subsequently, when the leading edge of the strip material 6 engages thesecond back-up roll 5, the respective actuator 12 is operated to effectvertical adjustment of this second roll 5, whereby the latter pressesthe strip material 6 to the respective'cleaning tools 21 and 23, inwhich way the rest of the lateral width of the strip material iscleaned.

With the herein disclosed apparatus constructed in accordance with thelast-described embodiment, there can be effected high-quality continuouscleaning of strip material and sheets of any length, as well as cleaningof relatively thin sheets which in this case retain complete (i.e., bothlongitudinal and lateral) stability against deformation by the frictionforces exerted thereupon by the rotating cleaning tools.

In case the total width 2b, of the tools 20 and 21 rotating in onedirection is in excess of the total width Eb of the tools 22 and 23rotating in the opposite direction, the difference between these twototal widths Ab should be, in accordance with the invention, not inexcess of the value of Ab, defined from the formula:

where f is the factor of slipping friction between the material beingcleaned and the back-up roll; F is the factor of friction or dragbetween the cleaning tool and the material being cleaned; B is thelateral width of the material being cleaned.

Let us now describe an example.

A strip material 6 having lateral width B equal to 2,000 mm is treatedby the rotating cleaning tools 20, 22 (FIG. 4) mounted on the shaft 1and tools 21, 23 mounted on the shaft 2.

The tools 20 and 21 have their width b, and are rotated in the directionof the arrow C, while the tools 22 and 23 have their total width b andare rotated in the direction of the arrow A.

In accordance with the invention, the tools 20, 21, 22, 23, 22, 21 and20 successively and alternatingly span the entire lateral width B of thematerial being cleaned, i.e.,

2b 21, B, i

ro) 2(1) m (1) where 1 1(1) ltll):

where 2b, is the total width of the tools rotated in the direction ofthe arrow C about the shaft l; 271 is the total width of the toolsrotated in the direction of the arrow C about the shaft 2. Similarly,let us express the total lateral width Eb of the tools rotated in thedirection of the arrow A in the form:

where Eb is the total width of the tools rotated in the direction of thearrow A about the shaft 1; Eb is the total width of the tools rotated inthe direction of the arrow A about the shaft 2.

The lateral width B of the strip material 6 is jointly spanned by thewidth of the tools mounted about the shaft 1 and the width of the toolsmounted about the shaft 2, i.e.,

B u) an, 7

and

BU) m) 2(1) un um zun where B is one part of the total lateral width ofthe strip material 6, spanned by the total width Ela of the tools 20 andby the total width Eb of the tools 22, mounted about the shaft 1;

B is the other part of the lateral width of the mate- I rial 6, spannedby the total width Eb of the tools 21 and by the total width Eb of thetools 23, mounted about the shaft 2.

Let us presume that B B 3/2; B B 1,000 mm and that the total width 2b,of the tools 20 mounted about the shaft 1 and rotated in one directionis in excess of the total width Zb of the tools 22 mounted about thesame shaft 1, but rotated in the opposite direction by a value AEb i.e.,

A212 is the difference between the total widths of the tools 20, 22mounted on the shaft 1.

in accordance with the invention, the value of the A21) should be not inexcess of the value Ab flF Lfir further presume that tiia'a'rr'eracarzbetween thetotal widths of the tools 20, 22 mounted about the shaft 1equals: A212 180 mm. With Ab 0.1 y 15 :50mn51/0 1,000 Bu mm tools 20, 22mounted about the shaft 1 equals:

Azbu mm.

Let us then determine from the expressions 5 and 7 '7 Let us now presurhe that the difference Aib of the the values of Zb and Zb 3O m) (1)UO/ 20) ro) m- Now we are able to calculate that: with F= 0.75 2b,=f(l,000 l)/2 590 mm.

Ebgu mm. with F= 0.30 Eb (1,000 480)/2 740 mm Zb 740 480 260 mm. 7 Letus presume (for the shaft 2) that the total width Zb ofthe tools 21mounted about the shaft 2 and rotatedin one direction is equal to thetotal width Erotated in b of the tools 23 mounted about the same shaft2, but rotated in the opposite direction, i.e.:

and then the difference AEb between the total widths of the tools 21 and23 becomes equal to 0.

Let us further calculate, for the shaft 2 in accordance with theinvention the value un f/ un- From the expressions 6 and 8 let usdetermine 217 and Ebzun: fll!) un an); 2 um un- Now we are able tocalculate that: with F 0.75

Zb 1 mm,

Eb 1,000 500 mm 500 mm, and likewise with F 0.30

Eb 500 mm Zb 500 mm.

We can see from the abovesaid that in the example that is beingdescribed, with the total width 2b, of the tools 20 equalling 590 mm,and the total width Eb of the tools 22 equalling 410 mm, the above toolsbeing mounted about the shaft 1, and with the total width Zb of thetools 21 equalling 500 mm and the total width Eb of the tools 23equalling 500 mm, these tools being mounted about the shaft 2, the stripmaterial 6 being cleaned (at a predetermined speed, without the materialslipping on the back-up roll) may have the width ranging from 2,000 mmto 1,640 mm, when F 0.75, or else from 2,000 mm to 1,400 mm, when F0.30, and that without varying the width of the cleaning tools mountedabout the shafts 1 and 2.

Therefore, it can be seen from the abovesaid that the herein disclosedapparatus offers wide operating capacities and facilitated performance.

The herein disclosed apparatus can employ effectively for the cleaningtools thereof rotaty cutting tools with radially arranged lengths ofwire, the lengths of wire being connected to one another adjacent to oneend thereof, the lengths being pressed to one another adjacent to theseconnected ends by their lateral surfaces, the opposite free ends ofthese lengths of wire making up a common cutting surface of the tool inthe form of a body of rotation, the ratio of the tool area of the facesof these free ends of the lengths of wire to the total area of thecutting surface of the tool being within a range from 0.2 to 0.9.

The employment of the abovespecified tools broadens still further theoperational abilities of the herein disclosed apparatus and considerablyimprovesits performance.

What we claim is:

1. Apparatus for cleaning strip material, comprising: in combination, aplurality of rotary cleaning tools, at least one pair of parallel shaftscarrying said cleaning tools; a plurality of back-up rolls forcooperation with said cleaning tools, each one of said back-up rollsbeing disposed in opposition to a respective one of said parallel shaftscarrying said cleaning tools to form nips therebetween, said nips beingspaced longitudinally from each other; said back-up rolls beingassociated with drive means for effecting positive forwarding of saidmaterial from a first nip to and through the next nip said back-up rollsbeing adapted for rotation in the direction of the forwarding of saidmaterial, one half of the total of said parallel shafts carrying saidcleaning tools also being adapted for rotation in the direction of theforwarding of said material, the other half of said total of saidparallel shafts being adapted for rotation in a direction opposite tothe forwarding of said material; one of said parallel shafts carryingsaid cleaning tools, which is the first one in said direction of saidforwarding of said material, being adapted for rotation in the course ofa cleaning operation only in a direction opposite to said direction ofsaid forwarding of said material.

2. An apparatus as claimed in claim 1, wherein at least one of saidparallel shafts carrying said cleaning tools and the respective one ofsaid back-uprolls arranged for cooperation therewith, are mounted foradjustment in the direction of said forwarding of said material.

3. An apparatus as claimed in claim 2, wherein each one of said parallelshafts carries thereon said cleaning tools rotated in oppositedirections to each other and so arranged in relation to one another thatthe linear speed of said material in the areas of the contact thereofwith the respective one of said back-up rolls is the same, the totallateral width of those of said tools that are rotated in one of saidopposite directions being essentially equal to the total width of thoseof said tools that are rotated in the other of said opposite directions,

all tools on said parallel shafts being so arranged with respect to eachother that the respective lateral widths thereof span the total width ofsaid material.

1. Apparatus for cleaning strip material, comprising: in combination, aplurality of rotary cleaning tools, at least one pair of parallel shaftscarrying said cleaning tools; a plurality of back-up rolls forcooperation with said cleaning tools, each one of said back-up rollsbeing disposed in opposition to a respective one of said parallel shaftscarrying said cleaning tools to form nips therebetween, said nips beingspaced longitudinally from each other; said back-up rolls beingassociated with drive means for effecting positive forwarding of saidmaterial from a first nip to and through the next nip said back-up rollsbeing adapted for rotation in the direction of the forwarding of saidmaterial, one half of the total of said parallel shafts carrying saidcleaning tools also being adapted for rotation in the direction of theforwarding of said material, the other half of said total of saidparallel shafts being adapted for rotation in a direction opposite tothe forwarding of said material; one of said parallel shafts carryingsaid cleaning tools, which is the first one in said direction of saidforwarding of said material, being adapted for rotation in the course ofa cleaning operation only in a direction opposite to said direction ofsaid forwarding of said material.
 2. An apparatus as claimed in claim 1,wherein at least one of said parallel shafts carrying said cleaningtools and the respective one of said back-up rolls arranged forcooperation therewith, are mounted for adjustment in the direction ofsaid forwarding of said material.
 3. An apparatus as claimed in claim 2,wherein each one of said parallel shafts carries thereon said cleaningtools rotated in opposite directions to each other and so arranged inrelation to one another that the linear speed of said material in theareas of the contact thereof with the respective one of said back-uprolls is the same, the total lateral width of those of said tools thatare rotated in one of said opposite directions being essentially equalto the total width of those of said tools that are rotated in the otherof said opposite directions, all tools on said paralLel shafts being soarranged with respect to each other that the respective lateral widthsthereof span the total width of said material.